An F-35B Lightning II with Marine Fighter Attack Squadron 121 takes off from Tinian in the Northern Mariana Islands, Jan. 30, 2025. (Dahkareo Pritchett/U.S. Marine Corps)

A Marine Corps F-35B Lightning II has returned to its home air station after undergoing maintenance for more than a month at a civilian airport in southern Japan, the service announced Monday.

The stealth jet, assigned to Marine Fighter Attack Squadron 121 at Marine Corps Air Station Iwakuni, landed at Kochi Airport on the afternoon of March 25 after the pilot received a warning indication during a routine training flight, 1st Marine Aircraft Wing spokesman Maj. Joseph Butterfield said at the time.

The F-35B made its return flight Monday after engineers and maintainers conducted “extensive troubleshooting, inspections and maintenance” at Kochi Airport, he said in an email to media that day.

The fighter returned around 3 p.m., Butterfield confirmed in a text message to Stars and Stripes. The cause of the precautionary landing is not under investigation, he added.

“We extend our sincere gratitude to the staff and leadership of Kochi Airport for their exceptional professionalism, hospitality, and support,” he wrote in the email. “Aviation safety remains our highest priority as we conduct training operations in support of the mutual defense of the United States and Japan.”

Kochi prefecture is on Shikoku, the smallest of Japan’s four main islands.

Commercial flights at the airport were not affected by the F-35B’s presence, a spokesman said on April 15. Some Japanese government officials customarily speak to the press on condition of anonymity.